Java 11与Java 8中的拖放工作方式不同

Question

我编写了一个程序,它使用了javafx中的拖放功能.在JavaFX8中它完美运行.

在JavaFX11中,拖放功能失效:我没有得到一个不同的鼠标光标,我没有得到我正在拖动的行的鬼图像,并且滴有些错误 - 它们不会触发鼠标释放,然后每次我点击表格时触发掉落.

这是最小的可运行示例,它演示了我面临的问题.在Java 8 JVM上运行它可以根据需要运行.在Java 11 JVM上它没有.我在Ubuntu 18.04上.

我很好地改变我的代码以适应Java 11,但我不知道我做错了什么.

Java 11版

java version "11.0.1" 2018-10-16 LTS
Java(TM) SE Runtime Environment 18.9 (build 11.0.1+13-LTS)
Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.1+13-LTS, mixed mode)

Java 8版

openjdk version "1.8.0_181"
OpenJDK Runtime Environment (build 1.8.0_181-8u181-b13-1ubuntu0.18.04.1-b13)
OpenJDK 64-Bit Server VM (build 25.181-b13, mixed mode)

DND11.java

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.scene.Scene;
import javafx.scene.control.SelectionMode;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableRow;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.input.ClipboardContent;
import javafx.scene.input.DataFormat;
import javafx.scene.input.Dragboard;
import javafx.scene.input.TransferMode;
import javafx.stage.Stage;

public class DND11 extends Application {

    public TableView<Person> getTable () {
        DataFormat DRAGGED_PERSON = new DataFormat ( "application/example-person" );

        TableColumn <Person, String> firstNameColumn = new TableColumn <> ( "First Name" );
        TableColumn <Person, String> LastNameColumn = new TableColumn <> ( "Last Name" );

        firstNameColumn.setCellValueFactory( new PropertyValueFactory <Person, String>( "firstName" ) );
        LastNameColumn.setCellValueFactory( new PropertyValueFactory <Person, String>( "lastName" ) );

        TableView <Person> tableView = new TableView <> ();
        tableView.getColumns().addAll( firstNameColumn, LastNameColumn );
        tableView.setColumnResizePolicy( TableView.CONSTRAINED_RESIZE_POLICY );

        tableView.setEditable( false );
        tableView.setItems( FXCollections.observableArrayList( Person.generatePersons ( 10 ) ) );

        tableView.getSelectionModel().setSelectionMode( SelectionMode.MULTIPLE );

        tableView.setRowFactory( tv -> {
            TableRow <Person> row = new TableRow <>();

            row.setOnDragDetected( event -> {
                if ( !row.isEmpty() ) {
                    Dragboard db = row.startDragAndDrop( TransferMode.COPY );
                    ClipboardContent cc = new ClipboardContent();
                    cc.put( DRAGGED_PERSON, row.getItem() );
                    tableView.getItems().remove( row.getItem() );
                    db.setContent( cc );
                }
            });

            row.setOnDragOver( event -> {
                Dragboard db = event.getDragboard();
                event.acceptTransferModes( TransferMode.COPY );
            });

            row.setOnDragDropped( event -> {
                Dragboard db = event.getDragboard();

                Person person = (Person)event.getDragboard().getContent( DRAGGED_PERSON );

                if ( person != null ) {
                    tableView.getItems().remove( person );
                    int dropIndex = row.getIndex();
                    tableView.getItems().add( dropIndex, person );
                }

                event.setDropCompleted( true );
                event.consume();
            });

            return row;
        });

        return tableView;
    }

    @Override
    public void start ( Stage stage ) throws Exception {
        stage.setScene( new Scene( getTable(), 800, 400 ) );
        stage.show();

    }

    public static void main ( String[] args ) {
        launch( args );
    }
}

Person.java

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

public class Person implements Serializable {

    private static final long serialVersionUID = 1L;

    private String firstName, lastName;

    public Person ( String firstName, String lastName ) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public String getFirstName() {
        return firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public static List <Person> generatePersons ( int number ) {
        List<Person> retMe = new ArrayList<Person> ( number );
        for ( int k = 0; k < number; k++ ) {
            retMe.add ( new Person ( randomFirstName(), randomLastName() ) );
        }
        return retMe;
    }


    private static Random rand = new Random();

    private static String randomFirstName() {
        return firstNames [ Math.abs( rand.nextInt() ) % firstNames.length ];
    }

    private static String randomLastName() {
        return lastNames [ Math.abs( rand.nextInt() ) % lastNames.length ];
    }

    private static String[] firstNames = new String[] {
        "ANTON","ANTONE","ANTONIA","NTONIO","ANTONY","ANTWAN","ARCHIE","ARDEN","ARIEL","ARLEN",
        "ARMAND","ARMANDO","ARNOLD","ARNOLDO","ARNULF","ARON","ARRON","ART","ARTHUR","ARTURO",
        "DARRICK","DARRIN","DARRON","DARRYL","DARWIN","DARYL","DAVE","DAVID","DAVIS","DEAN",

    };

    private static String[] lastNames = new String[] {
        "SMITH","JOHNSON","WILLIAMS","BROWN","JONES","MILLER","DAVIS","GARCIA","RODRIGUEZ",
        "WILSON","MARTINEZ","ANDERSON","TAYLOR","THOMAS","HERNANDEZ","MOORE","MARTIN","JACKSON"
    };
}

Answer 1

虽然JavaFX中的Drag and Drop具有适用于所有平台的通用API(当然,作为API的其余部分),但其内部实现依赖于平台,并且在Windows,Mac或Linux上完全不同.

但是,从JavaFX 8迁移到JavaFX 11时,这不应该是一个问题.

OP发布的示例在Windows和Mac上与JavaFX 8和11的工作方式相同,如果在Linux上不是这种情况,则可能与最新版本的JavaFX for Linux中所做的更改有关.

根据发布说明,在Important Changes我们可以看到的部分下面:

将默认GTK版本切换为3

现在,JavaFX将在存在gtk3库的Linux平台上使用GTK 3.在JavaFX 11之前,GTK 2库是默认的.这与JDK 11中AWT的默认值匹配.有关更多信息,请参阅JDK-8198654.

虽然这个改变基本上是JavaFX代码中的两行差异,并且没有从DND的实现细节改变,但GTK 3实现可能已经从GTK 2改变了,并且这些改变没有被考虑在内.

据报道,对话框,窗口或Wayland崩溃等与GTK相关的类似问题.

解决方法

到目前为止,所有这些问题的唯一已知解决方法是使用GTK 2运行应用程序,可以使用系统属性进行设置:jdk.gtk.version.

因此可以在命令行上添加此选项:

java -Djdk.gtk.version=2 ...

运行应用程序.

正如评论中所述,这似乎解决了拖放问题.

报告问题

当然,这确认这是一个问题,因此它应该在OpenJFX问题跟踪器中提交,提供重现它的示例代码,系统详细信息(操作系统版本,Java版本,JavaFX版本......).